Splutter - Splutter.....

[pfgiz]

Hi....

My wonderful traveller has just started exhibiting the classic signs of an over-rich mixture. IE: car dieing when the throttle is used. Under normal circumstances I've have re-adjusted it but it happend when I was at the in-laws yesterday evening, only there for a few hours, drove there ok but didn't want to come home. Can a carb suddenly start getting rich to this extent without anyone playing with the adjustments?

I've cleaned everything up, plugs, points, jet, dizzy cap, etc. Even fitted the 'spare' fuel pump, my poor sallon , all to no avail. Having had nothing but greif whenever I've tried to adjust a carb before, I come before you to ask if there is any other thing that could have happened that would present itself in this way? If not I will have to play with the mixture but wanted to cover bases first.

Thanks guys.

[Neil MG]

Most likely electrical. Misfiring on throttle could well be arcing and you would see that best in the dark. Also check the low tension wire inside the distributor. Condenser is an obvious contender...

Do you have a healthy spark?

There is very little that can go wrong with an SU carb. once set they normally never need touching.

Another thing that may cause sudden loss of carb. function is sticking piston. With the filter off just check that the piston rises and falls smoothly. Check that your choke is not jammed open or sticking open (jet fully up and return spring operating). Any other carb. issues would normally only be due to incorrect assembly, for instance a loose butterfly valve or missing/loose fixings or springs.

If you need to adjust the carb then only make adjustments when the car is running and then in small noted increments. e.g. When setting the mixture lift the piston 1/16" to 1/8" and if necessary adjust two flats and recheck.

[lambrettalad]

first thing I changed last week was the condenser ,same illness as yours ,fixed it in a jiff
good luck
now i have electronic ,as the modern condensers are c***,sorry rubbish

[bmcecosse]

It certainly won't have gone 'rich' - quite the opposite in fact. But I agree with the others - most likely sticky piston - or look at the ignition.

[pfgiz]

Cheers guys.... In the end, after much replacing of parts, it's all sorted. I'll post pictures and details in a new thread.....

On another point.... (pardon the punn).... What brackets do I need to mount a Lucas Alternator instead of the dynamo? I understand a 'long bolt' will do the job as a temporary measure but do the brackets off of any modern(?) A-series work or do they need to be specific???

[bmcecosse]

Bracket from an older A series is perfect - the later A+ engine has a shorter bracket - which won't pick up the holes on the A block. Yes - you can use a 'long bolt' (with or without a spacer tube) but it's not very satisfactory allowing the rear of the alternator to sag slightly, putting undue strain on the front mounting and tending to allow the pulley to run slightly out of true with detrimental effect on the belt, and eventually - the alternator bearings.